The mainland’s biggest LNG supplier is backing a move to introduce the fuel into Hong Kong’s transport market as an affordable solution to the city’s notorious roadside pollution problems.

China National Offshore Oil Corporation (CNOOC) is working with a local company on plans to introduce liquefied natural gas as vehicle fuel, with a vision of building a network of LNG refuelling stations similar to those found in mainland cities.

The partnership between CNOOC and the Hong Kong LNG Company will see the companies work with a cross-border coach operator to trial an LNG bus. But no refuelling facilities will be built yet because LNG is not covered by local laws. The bus will be refuelled in Shenzhen, which has at least 13 LNG refuelling stations to support hundreds of vehicles.

Zhu Jianwen, president of CNOOC Gas and Power Trading & Marketing, said Hong Kong was surrounded by a massive, robust LNG supply network and could take advantage of this.

The world’s third-largest LNG buyer, CNOOC imported almost 22 million tonnes last year. The Dapeng LNG terminal in eastern Shenzhen also supplies Hongkong Electric and Towngas via an underwater pipe.

While LNG fuel is said to be about 20 per cent cheaper than alternative vehicle fuels, Zhu said the gas could also offer a shortcut for the city to meet targets set down in its clean-air plan. Under the plan, published in March, the government wants to meet a yet-to-be-revealed set of air-quality objectives by 2020.

Zhu says LNG can help because it is free of particles and volatile organic compounds and generates lower levels of nitrogen oxides than other fuels.

But Zhu said the complexity of bringing LNG to Hong Kong should not be underestimated. Not only was there no legal framework, there was also a need to foster public acceptance and understanding of the fuel.

“Building a refuelling network with wide coverage will be the next stage of the plan. The most important thing for us now is to get a bus running,” he said.

James Wang Jianmin, executive director of Hong Kong LNG Company, said the partners would help a coach company apply to the Pilot Green Transport Fund to pay for the trial. They intend to buy a Swedish bus for more than HK$2 million.

Wang said senior environmental officials seemed positive about their ideas.

An Environmental Protection Department spokesman said the government was not convinced LNG would be cleaner than other fuel in meeting new, stricter emissions standards. There were other practical concerns and legal obstacles surrounding LNG.

But he added: “As the number of LNG vehicles grows in Guangdong, we do need to consider whether to enable these vehicles to come to Hong Kong.”

Mainland oil giant China National Offshore Oil Corporation (CNOOC) is working on plans to introduce liquefied natural gas for heavy vehicles in the city, yet the government concluded five years ago that the fuel had little future in Hong Kong.

The “Introducing Natural Gas/Liquefied Petroleum Gas Buses and Heavy Vehicles Feasibility Study Report” completed by the Electrical and Mechanical Engineering Department in 2009 cited the difficulties of locating suitable and adequate numbers of filling stations in the city.

In particular, it said LNG storage depots and refilling stations would need to be built locally to ensure supply security during typhoons. But land availability was an issue and there was always competing land use.

While CNOOC says LNG could be the safest transport fuel given its lighter density and high rate of evaporation, the report says refilling stations should have at least 55 metres’ clearance from the population to minimise risks.

Unlike the LNG refilling stations in Shenzhen, which have above-ground tanks, the report said Hong Kong’s fuel tanks should be installed underground and have their capacity capped. The report also gauged the emission-reduction potential of gas-fuelled vehicles and believed that the potential was comparatively small, because of advancements made in diesel engines.

World Green Organisation chief executive William Yu Yuen-ping agreed that infrastructure, like fuel storage or refilling stations, was the universal headache for harnessing new energy.

“Technology is hardly a problem for LNG. It is the infrastructure of fuel supply that really matters. The same also applies to electric vehicles or LPG vehicles,” he said. Yu added fuel stations were in the hands of oil giants and whether they could provide alternative fuel was always a question.

Another hurdle is meeting the fire safety regulations, which lay down detailed specifications for fire prevention.

Dr Hung Wing-tat, a transport expert at Polytechnic University, believed LNG might only be suitable for some fleet operators, who could provide refilling facilities at their depots. But he said it would be difficult to have the fuel widely available in Hong Kong’s uniquely dense environment because of space shortages.

LNG is an increasing popular “clean” fuel choice being adopted around the world in an attempt to reduce pollution.